Fault-Tolerant Scheduling of Non-preemptive Periodic Tasks using SCT of Timed DES on Uniprocessor Systems

Abstract

Safety-critical systems employ fault-tolerant strategies in order to provide predictable performance despite the occurrence of faults. Majority of faults that affect such systems are transient (i.e., momentary) in nature which can easily be tolerated through the re-execution of the affected task before its deadline. However, evaluating all possible fault patterns to provide an optimal re-execution based fault-tolerant scheduling strategy for a given task set is an intractable problem, and is prohibitively expensive to be applied on-line. Hence, off-line techniques are often preferred over on-line techniques for solving such problems. This work proposes an off-line optimal fault-tolerant scheduler synthesis mechanism for non-preemptive periodic real-time tasks on uniprocessors. Practical applicability of the above scheduler synthesis procedure has been illustrated through a motor network example.